The present invention is concerned with truck-mounted brake rigging and, more particularly, to a single-cylinder truck-mounted brake rigging arrangement employing truss-type brake beams.
Present day brake rigging for railway car trucks employ a pair of parallel, spaced-apart brake beams; each arranged to carry a brake cylinder device having a piston and a piston rod that is operatively-connected to the other brake beam, so that the respective brake beams are moved in opposite directions by the fluid pressure force acting in opposite directions on the bodies of the brake cylinder devices and the respective pistons thereof. Such a brake rigging is shown in U.S. Pat. No. 2,958,398, issued Nov. 1, 1960 to George K. Newell.
Specially designed brake beams are necessary in this type of brake rigging in order to support the weight of the brake cylinder mounted thereon, and to support the bending forces exerted on the beams during braking.
In order to alleviate the higher cost of these special brake beams, arrangements have been proposed which employ but a single, beam-mounted brake cylinder device, so that the expense of one special brake beam and associated cylinder is saved. These single cylinder arrangements, however, generally require a slack adjuster device when employed in actual service conditions, since all of the accumulated slack resulting from wear of the brake shoes at all four wheels is reflected in the piston travel of the single brake cylinder. The addition of a slack adjuster tends to offset any savings that would otherwise be realized by replacement of a single, special brake beam with a conventional truss-type brake beam.